The 4CX20,000A/8990 is a power tetrode intended for use in audio or radio frequency applications. It features an internal mechanical structure which results in high RF operating efficiency. Low RF losses in this structure permit operation at full ratings up to 110 MHz and at reduced ratings to 220 MHz. The 4CX20,000A/8990 has a gain over 18 dB in FM broadcast service, and is also recommended for radio frequency linear power amplifier service, and for VHF-TV linear amplifier service. The anode is rated for 20 kW of dissipation with forced air cooling and incorporates a new highly efficient cooler design, which significantly reduces air pressure and flow requirements and produces low acoustical noise. Class of Operation Characteristics Plate Dissipation (Max.) Screen Dissipation (Max.) Grid Dissipation (Max.) Frequency for Max. rating (CW) Amplification Factor Filament/Cathode Voltage Current Capacitance Input Output Feedthrough Capacitance Input Output Feedthrough Cooling Base Air Socket Air Chimney Boiler Length Diameter Weight Maximum Ratings Type of Service Plate Voltage (Volts) Plate Current (Amps) 20,000 Watts 450 Watts 200 Watts 110 MHz 6.7 Thoriated Tungsten 10.0 Volts 140 Amps Grounded Cathode 190 pf 23.5 pf 1.5 pf Grounded Grid 83 pf 24.5 pf 0.2 pf Forced Air Special, Coaxial SK-320 SK-326 --9.5 in; 341.3 mm 8.8 in; 223.5 mm 19.2 lb; 8.75 kg T ypical Operation Plate Screen Voltage Voltage (Volts) (Volts) Plate Current (Amps) Drive Output Power Power (Watts) (kiloWatts) C RF amplifier 10,000 5.0 9,000 900 4.0 26.4 28.2 C RF amplifier at 88.3 MHz 10,000 5.0 9,000 800 4.1 325 28.75 C RF amplifier at 107.7 MHz 10,000 5.0 9,000 800 4.2 360 28.9 The values listed above represent specified limits for the product and are subject to change. The data should be used for basic information only. Formal, controlled specifications may be obtained from CPI for use in equipment design. For information on this and other CPI products, visit our website at: www.cpii.com, or contact: CPI MPP Division, Eimac Operation, 607 Hansen Way, Palo Alto, CA 94303 telephone : 1(800) 414-8823. fax : (650) 592-9988 | email : [email protected] CPI | 4CX20,000A/ 8990 CPI | 4CW50,000J 4CX20,000A/8990